Strikecraft tend to be better in mass....I tend not to build any, or I want at least a couple. And I also put fighters in them as well, because they can pick off scouts trying to cross my systems, or they can destroy light siege raiders. You need a heck of a lot of defenses to stand up to a concentrated fleet.
Turrets are definately better than supporting each other when concentrated, but I almost never build them like this...I spread them out a bit, because I intend for them to beef up my fleet in defense. I can't tell you how many times I have flown around a turret cluster, burned the world from the other side, even colonizing it occasionally, and left the turret/repair bay cluster intact.
I think all of the strikecraft are pretty comparable and effective. One of the main things I find handy with Advent is that the carriers are easier to retreat before they are killed because they can take such a beating.